Edottard botjdreattx



June 12, 1923.

1,458,570 E. BOUDREAUX LEAD MOLDING USED IN GALVANOPLASTY Filed Nov. 5, 1921 Patented June 12, 1923.

UNITED sTATES EDOUARD BOUDREAUX, OF PARIS, FRANCE.

LEAD MOLDING USED IN GALVANOPLASTY.

Application filed November 5, 1921. SerialNo. 513,180.

To all whom it may concern I Be it known that I, Enouann BOUDREAUX, citizen of the French Republic, residing at 8 Rue Haute'feuille, Paris, France, have invented certain new and useful Improvements in Lead Moldings Used in Ga1vanoplasty, of which the following is a specification.

It is known that lead molding is more and more employed for the manufacture of galvanoplastic plates which are used for the reproduction of photoengravings. This molding necessitates the use of lead sheets relatively thin (about one millimeter) in order to avoid having recourse to too high pressures.

In practice, akind ofcushion formed of sheets of paper is interposed between the bed of the hydraulic press and the lead sheet.

This arrangement is adapted to facilitate the introduction of the lead in the large hollows or cavities of the engraving. However, the moldings thus obtained do not possess any rigidity and they are easily distorted by the strain which must be exerted for separating them from the types and by the manipulations of placing in the vats.

This invention has for its object a process allowing to give to the lead moldings a suflicient rigidity for permitting their manipulations, without the thickness of the molding plate being increased. For that purpose, there is interposed between the molding plate and a lead plate of greater or less thickness (which will be designated by the term carrying plate) a material of such composition that both plates'will be momentarily made integral with each other; the separation of the molding plate and of its carrying plate may be easily effected when desired and, for instance, when it is required to separate the lead impression from its galvanoplastic shell.

As indicated in the foregoing, another lead plate of greater or less thickness (or carrying plate) is placed before, during or after the impression, on the back of the molding plate remaining in contact with the type, after having interposed between the said plates a piece of canvas formed of thick threads impregnated with wax, mixed with pitch or with any other product or composition capable of adhering to the metal. The work is again placed under the press, so that the molded plate and the carrying plate are temporarily rendered sessesa sufficient rigidity forthe manipulations, since its total thickness may be of tour to five millimeters.

The rigidity can befurther increased by integral with each other; the Whole posreplacing the canvas by a wire gauze or a thickness of this armature. On the contrary, a single sheet of lead compressed on a wire gauze of this kind would penetrate throughout its thickness and would render difficult any subsequent separation.

The lead carrying plate might, moreover, be cast on a copper or brass plate previously tinned. Consequently, it would be integral with this sole which would receive the direct pressure ofthe press.

The molding may still be further facilitated by filling the meshes of the wire gauze, interposed between the two lead plates, with wax, gutta' percha or paraffin dissolved in turpentine or with any other similar composition. I

The same effect can be obtained by laying this mixture in the form of thin layers on the corresponding faces of the molding plate and or" the carrying plate between which is interposed the wire gauze. The plastic mixture determines a. partial obturation of the meshes of the wire gauze and thus constitutes small cells filled with air. This air serves as a resilient cushion when the pressure which must determine the molding is effected and acts, moreover, for facilitating the descent in the large blank spaces, hollows or cavities of the type. In these conditions, it is possible to do away with the cushion formed of sheets of paper.

which it was customary to interpose' between the plate of the press and the mold ing plate.

What I claim as my invention and desire to secure by Letters Patent is:

1. In an improved process for molding galvanoplastic plate consisting in applying a reticulated sheet to the lead sheet which takes the impression of the type and finally applying a sufficient amount of pressure for molding to temporarily render the sheets integral.

2. In an improved process for molding 'galvanoplastic plate consisting in applying a reticulated metallic plateto the back of the impression plate to reinforce the impression plate; then applying a stiffening lead core against the reticulated metal plate and finally applying pressure in an amount necessary for molding the impression on the type to effect temporary union of the plates and core.

3. In an improved process for molding signature.

ED OUARD BOUDREAUX. 

